The present invention relates to an insole or sole of shoes which seeks an effect of shock absorption during walking and also a massage effect owing to excitement of the sole of foot while providing for a stable and comfortable sense of wear.
The applicant has earlier proposed a sole or insole of shoes, which absorbs shock during walking while massaging a sole of foot by excitement thereof. The proposed sole or insole of shoes comprises a bottom plate, a plurality of blades formed integrally thereon, a cover with an outer periphery thereof bonded to an outer periphery of the bottom plate and fluid sealed in between the bottom plate and the cover. In more detail, a recess portion having a shape corresponding to a sole of foot is formed in an upper surface of the bottom plate. The blades are integrally formed on a bottom surface of the recess portion of the bottom plate. The blades are slanted and extend in directions perpendicular to a longitudinal direction of the bottom plate. The cover is formed with a recess portion having a shape corresponding to the sole of foot and an outer peripheral portion having a predetermined width surrounding the recess portion. The outer peripheral portion of the cover is welded to the outer peripheral portion of the bottom plate (cf. Japanese Patent No. 2549602, U.S. Pat. Nos. 5,189,816 or 5,365,678).
Further, the applicant has also proposed another sole or insole of shoes, in which grooves are formed in a middle portion of each of a plurality of blades so that fluid can be moved through these grooves. Outer end portions of a plurality of blades are connected to an inner end of a bottom plate through respective webs, each of which is lower than the blade to allow the fluid to pass therethrough (cf. Japanese Patent No. 1959712).
These proposals have been practically utilized in public favor.
The conventional insole or sole of shoes massages a sole of foot by excitement thereof during walking. It is general that, in walking, a heel portion of the sole of foot is landed, first, and, then, a tarsal portion of the sole, which includes an area of the sole from the heel to a substantial center portion of the sole is landed. Then, a metatarsal portion of the sole, which includes an area from the tarsal sole portion to roots of toes, is landed and, finally, the toes kick the land. By repeating these motions by the feet alternately, a wearer of the shoes can walk.
The recess portions of both the bottom plate and the cover of the conventional insole or sole of shoes, which are necessary for absorbing shock and massaging the sole of foot during walking, correspond in shape and size to the whole sole of foot including the toes and a space defined by these recess portions is filled with the fluid. Therefore, the kicking force of the toes during walking is absorbed by the fluid, causing the walking to be difficult. This difficulty may be similar to a case of walking on the sands. It has been found that this difficulty causes feet of some people, who have peculiarities in walking, troubles of internal organ and/or troubles of physiological function, to become numbing or painful, although this may cause no problem for normal people even when they walk for long time while exciting the effective spots existing in the roots of toes.
In the conventional insole or sole of shoes, the whole area of the bottom plate and the whole area of the cover, except their recess portions, are completely welded to each other by means of a high frequency welder and the whole welded area includes a relatively wide portion in front of the toes of the foot and narrow portions on both sides of the recess portions. Therefore, if a high frequency of high power is used in order to obtain a predetermined welding strength in the relatively wide portion, the welding strength of the whole welded area becomes non-uniform, causing the whole insole or sole to be distorted and/or causing the fluid to leak.
Further, the conventional blades are rectangle, have the grooves in the middle portions thereof and have the opposite end portions connected to an inner wall of the edge portions of the bottom plate through the webs. Therefore, in order to mold such blades, a metal mold having complicated configuration is required and the molding work itself is complicated. Further, in order to make the flow of fluid smooth, it is necessary to widen space through which the fluid flows, by making the blades higher than the webs by a predetermined amount. Therefore, the blades become so high that the thickness of the bottom plate has to be increased. This limits the wearing comfortableness of shoes and the freedom of design thereof.
Further, according to the conventional injection molding method of the bottom plate and the cover, which constitute the insole or sole of shoes, a gate of an injection molding metal mold is positioned in a location corresponding to an arch portion of foot. Therefore, a weld line of the injection molded bottom plate and the cover is frequently provided in a location on the side opposite to the position of the gate, which corresponds to an intermediate portion between a little toe and a second toe of foot. Further, a largest pressure is applied to the location of the insole or sole corresponding to the intermediate portion between the little toe and the second toe, during walking. Therefore, there is a problem that the fluid filing the space defined by the recesses tends to leak from a portion corresponding to the intermediate portion between the little toe and the second toe.
An object of the present invention is to provide an insole or sole of shoes, which absorbs shock during walking and massages a sole of foot owing to excitement of the sole of foot, while giving a stable and conformable sense of wear, has a plurality of easily formable blades and can prevent fluid from leaking by making a welding of a bottom plate and a cover reliable, and a manufacturing method of the insole or sole of the shoes.
Another object of the present invention is to provide an insole or sole of shoes, which has a bottom plate formed with a recess corresponding in configuration to a combination of the tarsal and metatarsal portions of foot, provides a stable and comfortable sense of walking unlike the unstable feeling of walking on the sands and does not provide any pain even when a wearer walks for a long time since the effective point existing in roots of toes is not excited at all or is substantially not excited.
Another object of the present invention is to provide an insole or sole of shoes, which has a plurality of blades formed on a bottom surface of a recess of a bottom plate and each having an arc ridge so that spaces are provided between opposite end portions of the arc blades and an inner wall of the recess portion of the bottom plate. With such simple structure of the blades, a manufacture of the metal mold therefor and the molding operation become simple.
A further object of the present invention is to provide an insole or sole of shoes, which has a plurality of arc shaped blades formed on a bottom surface of a recess portion of a bottom plate, end portions of the blades located in an area corresponding to an area between a little toe and a second toe or located in an area corresponding to an area between the little toe and a big toe being swollen so that a leakage of fluid by pressure can be prevented more reliably.
Another object of the present invention is to provide an insole or sole of shoes, in which a bottom plate having a recess portion and a cover having a recess portion are joined together by welding peripheral portions of the bottom plate and the cover, which directly surround the respective recess portions and have a uniform width, together so that, even if a high power, high frequency is used in order to obtain a predetermined welding strength, there is no twisting phenomenon of the whole insole or sole of shoes and the leakage of fluid can be prevented more reliably.
Another object of the present invention is to provide an insole or sole of shoes, in which a non-welded portion of the bottom plate and the cover is spot-welded in order to prevent sands or dusts from entering into between the non-welded bottom plate and the non-welded cover, in which an uneven pattern is formed in an upper surface of the cover in order to promote diffusion and evaporation of sweat and/or in which a sheet is attached to a lower surface of the bottom plate in order to reduce uncomfortableness when fluid leaks during walking.
The present invention resides in an insole or sole of shoes, which comprises a bottom plate, a plurality of blades formed integrally with the bottom plate, a cover welded to a peripheral portion of the bottom plate and fluid sealed in a space defined between the bottom plate and the cover, the bottom plate being formed of a thermoplastic resin and having a recess portion formed in an upper surface thereof, the blades formed in the recess of the bottom plate and extending in directions perpendicular to a longitudinal direction of the bottom plate and slanted toward a heel, wherein the recess portion formed in the upper surface of the bottom plate has a configuration corresponding to a tarsal portion of a sole of foot and a metatarsal portion of the sole of foot. The size of the recess portion may be the same as that of the tarsal portion and the metatarsal portion of foot or smaller analogously. It is preferable that a front-end portion of the recess portion does not reach roots of toes.
Each of the blades has an arc ridge form with opposite end portions being sloped gently down. There are provided spaces between the opposite end portions of the blades and an inner wall of the recess portion of the bottom plate. It is preferable that one end portions of some of the blades, which are located in an area corresponding to an area between a little toe and a second toe of foot may be swollen compared with the other end portions in order to reduce fluid pressure at those end portions of the blades.
In the insole or sole of the present invention, the bottom plate having the recess portion and the cover having the recess portion are joined together by welding the peripheral portions directly surrounding the respective recesses and having the uniform width together and the area surrounding the welded portion are not welded. It is preferable that surfaces of the bottom plate and the cover, which are not welded together, are spot-welded at a plurality of points. Further, it is preferable to form the uneven pattern on the cover. Further, it is preferable to attach the sheet to the lower surface of the bottom plate. The fluid has low permeability, is hardly evaporated and gets hardly bad. An antifreeze agent may be added to the fluid.